IN-VIVO TRANSFER OF LIPOPROTEIN(A) INTO HUMAN ATHEROSCLEROTIC CAROTIDARTERIAL INTIMA

The aim of this study was to compare the atherogenic potential of lipo protein(a) [Lp(a)] and LDL by measuring the intimal clearance of these two plasma lipoproteins in the atherosclerotic intima of the human ca rotid artery in vivo. Autologous I-131-Lp(a) and I-125-LDL were mixed and reinjected intravenously 3 hours before elective surgical removal of the arterial intima in four patients. The intimal clearance of Lp(a ) and LDL was 229+/-48 and 405+/-127 nL/cm(2) per hour, respectively ( paired t test; P=.12). The mass accumulation of Lp(a) (114+/-32 ng/cm( 2) per hour) was on average one 15th that of LDL (paired t test; P=.06 ), mainly reflecting a low plasma concentration of Lp(a) compared with LDL in the human subjects studied. In accordance with our previous ob servation in rabbits, there was a positive association between the int imal clearance of LDL and that of Lp(a) (r=.97, P=.03). Accordingly, h igh plasma levels of Lp(a) may share with LDL the potential for causin g lipid accumulation in the arterial intima in humans.